Hydraulic drive for a circular knitting machine

ABSTRACT

THE NEEDLE CYLINDER OF A CIRCULAR KNITTING MACHINE IS ROTATED BY A FLUID OPERATION MOTOR WHOSE SPEED AND DIRECTION OF ROTATION IS CONTROLLED BY VALVE MEANS, INCLUDING PROGRAM CONTROLLED VALVES.

HYDRAULIC DRIVE FOR A CIRCULAR KNITTING MACHINE Filed Jan. 16, 1969 J. KURKA March 16, 1971 3 Sheets-Sheet 1 I WI INVENTOR 31R! BY ATTORNEY Ila March 16, 1971 J. KURKA 3,570,267

HYDRAULIC DRIVE FOR A CIRCULAR KNITTING MACHINE Filed Jan. 16, 1969 3 Sheets-Sheet 2 age Q81: 68 l ll l 74 74 l 5 75' Z Z I l 7 S nnn Lo O i L i l I INVENTOR Tim 00431.4. f BY A find w.

ATTORNEY March 16, 1971 J. KURKA 3,570,267

HYDRAULIC DRIVE FOR A CIRCULAR KNITTING MACHINE Filed Jan. 16, 1969 3 Sheets-Sheet 5 sod jaw 361 A 1 z v 6 P 3 iii INVENTOR Tm: KMRKA- ATTORN EY United States Patent O 3,570,267 HYDRAULIC DRIVE FOR A CIRCULAR KNITTING MACHINE Jiri Kurka, Trebic, Czechoslovakia, assignor to Elitex- Zavody textilniho strojirenstvi generalni reditelstovi,

Liberec, Czechoslovakia Filed Jan. 16, 1969, Ser. No. 791,608 Int. Cl. D04b 9/00 US. Cl. 66-56 12 Claims ABSTRACT OF THE DISCLOSURE The needle cylinder of a circular knitting machine is rotated by a fluid operation motor whose speed and direction of rotation is controlled by valve means, including program controlled valves.

BACKGROUND OF THE INVENTION The present invention relates to a drive for circular knitting machines having one or several feeding stations, or one or several heads.

The known drives for circular knitting machines include gear transmissions transferring rotary motion from an electric motor to the needle cylinder of the knitting machine. For knitting the heel part of a stocking, it is necessary to reverse the rotary motion of the needle cylinder which is accomplished by clutches connecting and disconnecting gears.

Other known drives employ asychronous electric motors which can be set to rotation at different speeds. It is also known to use an electromagnetic clutch between an electromagnetic drive motor and a drive pulley connected with the circular knitting machine.

The electro mechanical drives according to the prior art are expensive to manufacture and operate noisily. Furthermore, the structure is rather complicated and requires considerable and frequent servicing to maintain the drive in a perfect operating condition.

SUMMARY OF THE INVENTION It is one object of the invention to overcome the disadvantages of the known drives for circular knitting machines, and to provide a circular knitting machine with a hydraulic drive which is inexpensive to manufacture, and produces little noise during operation.

Another object of the invention is to adjust the speed of the motor, and to vary the direction of rotation of the motor, by valves in conduits connecting the motor with a pump.

In the preferred embodiment of the invention, program controlled throttling valve means are disposed in the conduits and control the amount of fluid supplied to the motor, and thereby the rotary speed of the motor and circular knitting machine. Reversing valve means are provided for reversing the direction of rotation of the fluid motor and the knitting machine.

It is advantageous to operate the reversing valve means by electromagnets controlled by switches.

In the preferred embodiment, a distributing valve, controlled by electromagnetic means, selectively directs fluid supplied by a pump into two distributing conduits, in each of which a program controlled throttling valve is provided, and an amount of fluid in accodrance with the respective program, is supplied by one or the other distributing conduits to the reversing valve means.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic view schematically illustrating a hydraulic circuit according to the invention for rotating the needle cylinder of a circular knitting machine;

FIG. 2 is a fragmentary sectional view illustrating a part of the hydraulic circuit including a pump and filters;

FIG. 3 is a fragmentary sectional view forming a continuation of FIG. 2 and illustrating a portion of the hydraulic circuit including a distributor valve and two program controlled throttling valves; and

FIG. 4 is fragmentary schematic view forming a continuation of FIG. 3 and illustrating reversing valve means and a fluid motor.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIGS. 1 and 2, the needle cylinder 1 of a circular knitting machine has a bottom part provided with a gear ring meshing with a pinion 11a which is fixed to the shaft 21 of a fluid operated motor 2 of the West or wobble plate type. In the illustrated embodiment, oil is used for operating motor 2.

Shaft 21 is mounted in bearings 26 and is connected by a key 25 to a rotor 24 in which axial pistons 23 are mounted in a position abutting a rotary slanted support disc 22. Pressure oil is supplied to the cylinders of the axial pistons 23 through feed ducts 27 from main channels 28 and inlet openings 29 through conduit means A7 or B4 which effect opposite rotation of rotor 24 and shaft 21. The used pressure oil is discharged through return conduit means C6 or C7. Reversing valve means 3 have a body 32 in which a valve slide 31 is mounted for movement between two positions. An electromagnet 33 is connected into a control circuit 34 by means of a switch 35 and acts on valve slide 31 against the action of spring 38 disposed between an abutment 0n valve slide 31 and valve body 32.

Valve body 32 has an inlet opening 36b to which two distributor conduits A6 and B3 are connected, and outlet openings 37a, 37b to which conduits A7 and B4 are connected. Outlets 36a and 360 are connected with return conduits C6 and C7 and a common return conduit C8 leading through an expansible diaphragm sleeve 4 to a further portion C9 of the return conduit.

Spring 38 holds valve slide 31 in a normal position in which pressure oil is supplied from distributor conduits A6 or B3 through inlet 36b, outlet 37a to conduit A7, but when electromagnet 33 is energized by operation of switch 35, see FIG. 1, valve slide 31 is shifted, and the pressure oil is supplied through conduit B4 to motor 2 so that rotation of shaft 21 with pinion 11a and needle cylinder 1 is reversed from the direction of rotation S1 to direction of rotation S2.

Portions A6 and B3 of the distributor conduits are connected through pressure valves 5 and 5' to other portions A5 and B2 which respectively lead to throttling valves 6 and 6', as shown in FIG. 3. Pressure valves 5 and 5' have valve bodies 51, 51' in which pistons 52 and 52' are movably mounted. The valve bodies 51 and 51 have inlet openings connected with the distributor conduits A5 and B2, respectively, so that the pressure of the oil in the same presses the pistons 52, 52 from the illustrated closing position abutting a seat, to an open position against the action of the springs 53, 53'. Pressure valves 5, 5' maintain a desired pressure in conduits A6 and B3, and disconnects hydraulic motor 2 if the pressure is too low for proper operation.

Portions A and B2 of the distributor conduits receive pressure oil from outlets 63, 63' of throttling valves 6, 6' which receive pressure fluid from portions A4 and B1 of the distributor conduits respectively connected with inlets 62, 62' of throttling valves 6, 6. Inlets 62, 62' and outlets 63, 63' are provided in tubular portions of valve bodies 61, 61 which also have outlets 64, 64 connected with return conduits C4 and C5 which discharge into the main return conduit C9.

Throttling valves 6, 6 have cylindrical chambers 68, 68 in which the rotary control valve members 67, 67 are mounted. Shafts 67a and 67a of control valve members 67, 67 are preferably operated by known program control means. When control valve slides 67, 67 are turned in the direction of the arrows S, S, the amount of oil flowing through throttling valves 6, 6' is varied. In the event that the pressure of the oil fed into inlet opening 62, 62' is greater than the adjusted pressure of spring 65, 65' biassing slide 66, 66', the force of spring 65, 65' is overcome and slide 66, 66' moves against the action of spring 65, 65' so that excess oil is discharged through gvertow outlet 64, 64 into the return conduit means C4,

A distributor valve means 7 controls the flow of oil from the pump conduit A3 into one of the distributor conduit portions A4, B1. Distributor valve 7 has a valve body 71 in which a slide valve 72 is mounted for movement between three positions. Electromagnets 73, 73' act on the slide valve 72, when selectively energized, to move the same against the action of the springs 78, 78' to a first position in which a duct in slide valve 72 connects inlet 76b with outlet 77a, and a second position in which inlet 76b is connected with outlet 77b so that conduit A4 or B1 is supplied with pressure oil. In the illustrated intermediate position of slide valve 72, pump conduit A3 is disconnected from both distributor conduits A4 and B1. Outlets 76a and 76c are connected with a return conduit C9 communicating with a main return conduit C9.

As shown in FIG. 1, electromagnets 73, 73 are connected into circuits 75, 75' and energized and deenergized by closing and opening switches 74, 74'.

As shown in FIG. 2, pump conduit portion A3 is connected with the outlet 83 of a filter 8 whose inlet 82 is connected by pump conduit portion A2 to the outlet 105 of a transfer valve whose inlet 104 is connected by pump conduit portion A1 to the outlet 93 of a gear pump 9 whose inlet 92 is connected by suction conduit A to a reservoir 12 in which the operating oil 13 is maintained at a predetermined level.

Filter 8 has a housing 81 in which a cylindrical filter 84 consisting of a textile fabric is mounted on a tubular member 85 so that oil entering through inlet 82 passes through filter 84 and the openings in tubular member 85 and the interior of the same to outlet 83 so that impurities contained in the oil are removed.

Transfer valve 10 has a valve body 101 in which a slide valve 102 is mounted for movement between the illustrated position in which it is held by spring 103, and a displaced position. In addition to outlet 105 and inlet 104, valve body 101 has an outlet 108 opening into a return conduit portion C1 which is connected with inlet 104 when valve slide 102 is shifted to a displaced position against the action of spring 103. Valve body 101 has a duct 106 which connects the cylinder bore in which valve slide 102 is mounted, with a spring loaded safety valve 107. Valve slide 102 has an annular groove which in the displaced position of valve slide 102 connects inlet 104 with return outlet 108, and outlet 105 with duct 106 of safety valve 107.

Pump 9 which pumps oil through pump conduit portion A1 into inlet 104 of transfer valve 10, is a gear pump having a housing 91 in which a pair of meshing gears 94, 95 is mounted for rotation in opposite directions. Shaft 96 is driven in the direction of the arrow 53 and connected by a key 97 with gear 95 for rotating the same with a meshing gear 94.

When slide valve 102 of transfer valve 10 is shifted to the right as viewed in FIG. 2, pump conduit portions A1 and 2 are disconnected, and the oil pumped by pump 9 into return conduit C1 enters the inlet 114 of a filter device 11 whose outlet 115 is connected by a return conduit C2 to a reservoir 12 so that by actuation of transfer valve 10, idle circulation of the oil pumped by pump is obtained without operation of hydraulic motor 2 and needle cylinder 1. Manual means, not shown, are provided for setting transfer valve 10 between the idling and operative positions.

Filter device 11 has a housing 111 in which a stack of discs 112 is located, mounted on bolts and held together by a spindle 113 which can be manually turned. Oil returned through return conduit C1 passes between the slots formed by discs 112 before flowing into return conduit portion C2, and is cleaned of large impurities, filter device 11 being a coarse filter, while filter device 81 is a fine filter.

OPERATION The electric motor by which shaft 96 is driven is started so that the pump 9 pumps oil from reservoir 12 through conduit A, A1 into the transfer valve 10 which may be in the position in which the pumped oil is returned through return conduits C1, C2 and filter device 11 to the reservoir so that the oil is idly circulated while being filtered. When transfer valve 10 is set to the illustrated position, the pressure oil flows through the transfer valve and out of outlet 105 through conduit 2 into the fine filter 8 and from there through conduit A3 to the distributor valve 7. In the event that the flow in conduit means A2 to A7 is blocked, the pressure in transfer valve 10 is increased and slide valve 102 is displaced against the action of spring 103 to assume the idling position in which all oil pumped by pump 9 is returned through return conduits C1 and C2 to the reservoir. At the same time, duct 106 of the safety valve 107 is connected with the inlet 105 and the outlet 101 by the annular groove in slide valve 102 so that the excess pressure of the oil in conduit A2 is reduced before the oil enters the return conduit C1.

In a normal position of transfer valve 10, oil is pumped through conduit A3 into inlet 76b of distributor valve 7. By controlling slide valve 72 by electromagnets 73, 73', starting and stopping of hydraulic motor 2 are obtained.

When switch 74 is closed, current flows in circuit 75 to the winding of electromagnet 73' which moves slide valve 72 in the direction of the arrow P5 against the action of spring 78' so that the pressure oil from conduit A3 flows through outlet opening 77a into distributor conduit A4 and from there to the inlet 62 of throttling valve 6. The oil flows around throttling piston 66 into chamber 68. By turning control slide 67 in the direction of the arrow S, the quantity of the pressure oil flowing through throttle valve 6 is adjusted since throttling piston 66 permits only a limited amount of oil to flow from inlet 62 to outlet 63, which are also connected by control valve 67, chamber 68 and corresponding ducts 68a, and 68b. It is advantageous to operate control valve 67 by an automatic programming device, which may be a mechanical, electronic, or electromagnetic apparatus. For example, the position of control slide 67 may be determined by a pattern chain, or controlled by electronic means including a pickup reading out a program tape.

In the event that throttling valve 6 throttles the flow to a very high degree, the force of spring 65 is overcome by the throttling piston 66, and throttling piston 66 opens outlet 64 so that the oil supplied by conduit A4 flows through return conduit C4 into the main return conduit C9 which discharges into reservoir 12.

An adjusted amount of pressure oil flows through conduit A5 to the presseure valve 5 which opens when the oil in conduit A5 has a suflicient pressure so that the oil flows through conduit A6 into inlet 36b of reversing valve 3.

In the event that switch 74 is opened, and switch 73 closed, electromagnet 73 is energized and shifts slide valve 72 in the direction of the arrow P4 against the force of 78' so that pressure oil supplied by conduit A3 to the inlet 76b is guided out of outlet 77b and into portion B1 of the second distributor conduit. The pressure oil passes from conduit portion B1 into inlet 62' of throttling valve means 6 and out of outlet 63' through conduit portion B2 and pressure valve B and conduit portion B3 into inlet 36b of reversing valve 3.

If instead of the first distributor conduit A4 to A6, the second distributor conduit B1 to B3 is selected the operation of distributor valve 7 the amount oil flowing to reversing valve 3 can be adjusted by control valve 67', preferably automatically by program controlled means, in the same manner as described with respect to throttling valve 6. In the intermediate normal position of the distributor valve 7, no oil flows from conduit A1, A2, A3 into the distributor conduits A4 to A6 and B1 to B3, and the motor 2 stops.

Irrespective of which distributor conduit supplies pressure fluid to the reversing valve 3, slide valve 31 is held by spring 38 in a normal position in which pressure fluid flows through conduit A7 into motor 2 and rotates the same in one direction of rotation, together with needle cylinder 1. When switch 35 is closed, electromagnet 33 is energized and shifts valve slide 31 to a position in which pressure oil is supplied through the conduit B4 to motor 2 in such a manner that the needle cylinder 1 is rotated in the opposite direction, as indicated by arrows S1 and S2 in FIG. 1.

When hydraulic motor 2 rotates the needle cylinder in the direction of the arrow S1, the used oil flows from motor 2 through return conduit C7, and openings 37b, 36c into return conduit C8 and from there through main return conduit C9 into the reservoir 12.

If reversing valve is shifted, and pressure fluid is supplied to motor 2 through conduit B4, so that the needle cylinder 1 rotates in the direction of the arrow S the used oil flows through return conduit C6, and openings 37a, 36a into return conduit C8.

By operating switch 35, reversing valve means 3 is operated to cause reversal of direction in which the knitting machine is rotated. Assuming that distributor conduit A4 to A6 is connected with reversing valve 3, the speed of rotation in either direction depends on the setting of control valve 67, or on the porgram controlled adjustment of the same. By shifting distributor valve 7 to the other position in which distributor conduits B1 to B3 is connected with the reversing valve 3, while distributor conduit A4 to A6 is disconnected therefrom, motor 2 and the needle cylinder 1 will continue to rotate in the same direction as before, but the speed of rotation will depend on the manual or automatic setting of control valve 67' in throttling valve 6.

By shifting the distributor valve 7 to render valve 6' effective instead of valve 6, the speed of motor 2 and of the driven needle cylinder may be changed from a low speed to a very high speed.

It is evident that a different type of hydraulic motor may be substituted for the described motor 2, and that the speed controlling valves 6 and 6, and other elements of the hydraulic circuit, may be diiferently constructed.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of hydraulic drives different from the types described above.

While the invention has been illustrated and described as embodied in a hydraulic drive for driving a circular knitting machine at diiIerent speeds and in opposite directions, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

1. Hydraulic drive for a circular knitting machine comprising, in combination, a fluid operated motor connected with the circular knitting machine for driving the same; conduit means for supplying a fluid to, and for discharging the fluid from said motor; pump means for supplying pressure fluid into said conduit means; valve means in said conduit means for controlling the speed of said motor and knitting machine, and including a reversing valve for controlling the direction of rotation of said motor and knitting machine and connected by said conduit means with said pump means; and control apparatus for operating said valve means and including control means for selectively operating said reversing valve for reversing said motor and thereby said knitting machine.

2. Hydraulic drive as claimed in claim 1 wherein said reversing valve has first and second positions; wherein said conduit means include first and second conduits connecting said reversing valve in said first and second positions, respectively, with said motor for driving the same forward and reverse, respectively; and wherein said control means selectively place said reversing valve in said first and second positions for reversing said motor and thereby said circular knitting machine.

3. Hydraulic drive as claimed in claim 2 wherein said control means include electromagnetic means, and switch means controlling said electromagnetic means to shift said reversing valve between said first and second positions.

4. Hydraulic drive as claimed in claim 2 wherein said valve means include throttle valve means in said conduit means; and wherein said control means include means for operating said throttle valve means to adjust the amount of fluid flowing through said conduit means so that the speed of said motor and of said circular knitting machine is varied.

5. Hydraulic drive as claimed in claim 1 wherein said valve means include a distributor valve having first and second distributing positions and a closed position, reversing valve having first and second reversing positions; wherein said conduit means include a pump conduit connecting said pump means with said distributor valve, first and second distributor conduits connecting said distributor valve in said first and second distributing positions, respectively, with said reversing valve, and first and second reversing conduits connecting said reversing valve in said first and second reversing positions, respectively, with said motor for driving the same in forward and reversed directions, respectively; said apparatus including first control means for moving said distributor valve from said closed position to said first and second distributing positions, and second control means for operating said reversing valve between said first and second reversing positions; first adjustable throttle valve means in said first distributor conduit; and second adjustable throttle valve means in said second distributor conduit for adjusting the amount of fluid flowing through said first and second distributing conduits, respectively, to said reversing valv whereby the direction of rotation of said motor is reversed in said second reversing position, and whereby the speed of said motor depends in said first and second distributing positions of said distributing valve on the adjustment of said first and second throttling valves, respectively.

6. Hydraulic drive as claimed in claim 5 wherein said first and second throttling valves are program controlled.

7. Hydraulic drive as claimed in claim 5 wherein said first and second control means include first and second electromagnetic means, respectively, and first and second switch means for energizing the same; and wherein said distributor valve and said reversing valve each include a movable valve member actuated by said first and second electromagnetic means, respectively.

8. Hydraulic drive as claimed in claim 5 Comprising filter means in said pump conduit; pressure valves in said first and second distributing conduits; and a transfer safety valve in said pump conduit opening at high pressure to return pumped fluid to said pump.

9. Hydraulic drive as claimed in claim 8 wherein said conduit means include return conduit means connecting said motor with said reversing valve, and said reversing valve, and transfer safety valve with the suction side of said pump means.

10. Hydraulic drive as claimed in claim 1 wherein said valve means include at least one other valve in said conduit means for stepless adjustment of the rotory speed of said rotor; and wherein said control apparatus includes other control means for operating said other valve.

11. Hydraulic drive as claimed in claim 1 wherein the knitting machine has a rotary needle cylinder; wherein said fluid operated motor has a shaft; and comprising gear means connecting said shaft with said needle cylinder.

12. Hydraulic drive as claimed in claim 1 wherein said control apparatus includes means for preventing overrunning of said motor.

References Cited UNITED STATES PATENTS RONALD FELDBAUM, Primary Examiner 

